ES2752461T3 - Process to produce 2,3,3,3-tetrafluoropropene - Google Patents

Abstract

A process for reducing the polymerization of a starting reagent comprising: providing a liquid phase composition comprising a compound of formulas I, II and/or III CX2=CCl-CH2X (Formula I) CX3-CCl=CH2 (Formula II ) CX3-CHCl-CH2X (Formula III) and one or more supplementary organic compounds other than the compound of formulas I, II and/or III, wherein X is independently selected from F, Cl, Br and I, with the proviso that at least one X is not fluorine; and heating said starting composition to form a vapor phase composition, said supplemental organic compound being present in an amount ranging from 1 to 50% by weight, preferably from 3 to 30% by weight and more preferably from 5 to 15% by weight and wherein said organic filler is a halocarbon or haloolefin and has a boiling point that is lower than the boiling point for the compound of Formulas I, II or III and wherein the organic filler is chemically compatible with the compound of Formulas I, II or III and with hydrogen fluoride.

Description

DESCRIPTION

Process to produce 2,3,3,3-tetrafluoropropene

Cross reference to related requests

Field of the Invention

The present invention relates to a process for preparing fluorinated organic compounds, more particularly to a process for preparing fluorinated olefins and even more particularly to a process for producing 2,3,3,3-tetrafluoropropene (HFO-1234yf).

Background of the Invention

Hydrofluoroolefins (HFOs), such as tetrafluoropropenes (including 2,3,3,3-tetrafluoropropene (HFO-1234yf)), are now known to be effective refrigerants, extinguishers, heat transfer media, propellants, blowing agents, agents. blow molding, gaseous dielectrics, sterilizing vehicles, polymerization media, particle removal fluids, vehicle fluids, abrasive polishing agents, displacement drying agents and power cycle working fluids. Unlike chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs), both of which potentially harm the Earth's ozone layer, HFOs do not contain chlorine and therefore do not pose a threat to the ozone layer. HFO-1234yf has also been shown to be a low global warming compound with low toxicity and therefore can meet increasingly stringent requirements for refrigerants in mobile air conditioning. Accordingly, HFO-1234yf-containing compositions are among the materials being developed for use in many of the applications mentioned above.

Various methods of HFO preparation are known. For example, Pat. from USA No. 4,900,874 (Ihara et al.) Describes a method of making fluorine-containing olefins by contacting hydrogen gas with fluorinated alcohols. Although this appears to be a relatively high throughput process, commercial scale handling of high temperature hydrogen gas is dangerous. Furthermore, the cost of commercially producing hydrogen gas, such as building an on-site hydrogen plant, is economically expensive.

The Pat. from USA No. 2,931,840 (Marquis) describes a method of making fluorine-containing olefins by pyrolysis of methyl chloride and tetrafluoroethylene or chlorodifluoromethane. This process is a relatively low yield process and a very large percentage of the organic starting material is converted into unwanted and / or unimportant by-products, including a considerable amount of carbon black which tends to deactivate the catalyst used in the process.

The preparation of HFO-1234yf from trifluoroacetylacetone and sulfur tetrafluoride has been described (see Banks, et al., Journal of Fluorine Chemistry, Vol. 82, Art. 2, p. 171-174 (1997)). Furthermore, Pat. from USA No. 5,162,594 (Krespan) discloses a process where tetrafluoroethylene is reacted with another fluorinated ethylene in the liquid phase to produce a polyfluoroolefin product.

US 2011/245548 discloses a process for preparing 2-chloro-3,3,3-trifluoropropene where 1,1,2,3-tetrafluoropropene is heated with HF in the vapor phase and oxygen is present as a supplement. US 2009/240090 discloses a process for preparing 2-chloro-3,3,3-trifluoropropene where 1,1,2,3-tetrafluoropropene in vapor phase and 1,1,1,2,3-pentachloropropane it is present as a supplement.

However, there remains a need for an inexpensive means to produce hydrofluoroolefins, such as HFO-1234yf. The present invention satisfies this need among others.

Summary of the invention

The present invention relates, in part, to one or more process steps to improve the reaction efficiency used for HFO production, such as 2,3,3,3-tetrafluoropropene (1234yf) as set forth in the claims. In one aspect, the present invention relates to a process for reducing polymerization of a starting reagent during the manufacture of 1234yf by heating a starting reagent composition in a liquid phase including at least one compound of formula I, II and / or III

CX2 = CCl-CH2X (I)

CXa-CCl = CH2 (II)

CXa-CHCl-CH2X (III)

and an effective amount of one or more supplemental compounds other than the compound of formula I, II and / or III. "X", as used in any of the formulas I, II and / or III, is independently selected from F, Cl, Br and I. At least one X is not fluorine. The starting composition is heated in such a way that it forms a vapor phase composition.

In a further aspect, the present invention relates to a process for preparing 2-chloro-3,3,3-trifluoropropene by providing, in a liquid phase, a starting composition that includes at least one compound of formula I, II and / or III

CX2 = CCl-CH2X (I)

CXa-CCl = CH2 (II)

CX3-CHCl-CH2X (III)

as defined above and also an effective amount of one or more supplemental organic compounds, other than the compound of formulas I, II or III. The starting composition is vaporized to form a vapor phase composition and then contacted with a fluorinating agent to produce a final composition comprising 2-chloro-3,3,3-trifluoropropene.

In any of the foregoing embodiments, or in any embodiment provided herein, at least one compound of formula I, II, or III has at least one X is chlorine. In further embodiments, at least one compound of formula I, II, or III has chlorine at each X position. In still further embodiments, at least one compound of formula I includes 1,1,2,3-tetrachloropropene and / or at least one compound of formula II includes 2,3,3,3-tetrachloropropene and / or at least one compound of formula III includes 1,1,1,2,3-pentachloropropane.

The organic co-feed compound can be any organic compound that improves the above process, particularly by decreasing oligomerization / polymerization of the starting reagent and / or reducing catalyst deactivation throughout the process. In one embodiment, the supplemental organic compound has a boiling point that is lower than the compound of Formula I, II, or III. Such compounds include halocarbons or haloolefins, of which one or more of the following may be included: trichlorofluoropropene (1231), 2,3-dichloro-3,3-difluoropropene (1232xf), 1,2-dichloro-3,3, 3-trifluoropropene (1223xd), 2-chloro-3,3,3-trifluoropropene ^{(1233xf), 2-chloro-1,1,1,2-tetrachloropropane (244bb), 1,1,1,2,2-pentafluoropropane (HFC-245cb), difluoromethane} (HfC-32), pentafluoroethane (HFC-125), 1,1,1,2-tetrafluoroethane (HFC-134a), trifluoroethane (HFC-143) (including all isomers thereof) , 1,1,1,3,3-pentafluoropropane (HFC-245fa).

The effective amount of the supplemental compound can be any amount provided herein. Although not limited thereto, in certain respects it is between about 0.1 and about 99.9% by weight, between about 1 and about 50% by weight, between about 3 and about 30% in weight or between about 5 and about 15% by weight, each based on the total amount of organic food provided to the reaction.

The step of contacting the starting composition with a fluorinating agent can occur in the presence of a catalyst. In one aspect, the contact stage occurs in a vapor phase with or without the presence of a vapor phase catalyst. Vapor phase catalysts used for such a reaction include, but are not limited to, a chromium oxide, a chromium hydroxide, a chromium halide, a chromium oxyhalide, an aluminum oxide, an aluminum hydroxide, a aluminum halide, an aluminum oxyhalide, a cobalt oxide, a cobalt hydroxide, a cobalt halide, a cobalt oxyhalide, a manganese oxide, a manganese hydroxide, a manganese halide, a manganese oxyhalide, a nickel oxide, a nickel hydroxide, a nickel halide, a nickel oxyhalide, an iron oxide, an iron hydroxide, an iron halide, an iron oxyhalide, inorganic salts thereof, fluorinated derivatives thereof and combinations thereof. In certain embodiments, the catalyst includes a chromium oxide, such as, but not limited to, Cr2O3.

In still further aspects, the present invention relates to a process for preparing 2,3,3,3-tetrafluoroprop-1-ene

to. providing a starting composition that includes a compound of formula I, II and / or III

CX2 = CCl-CH2X (I)

CX3-CCl = CH2 (II)

CX3-CHCl-CH2X (III)

wherein X is independently selected from F, Cl, Br and I, provided that at least one X is not fluorine;

b. vaporizing said starting composition with an effective amount of one or more organic compounds supplementary, other than the compound of formula I, II or III;

c. contacting the starting composition with a first fluorinating agent to produce a first intermediate composition including 2-chloro-3,3,3-trifluoropropene and a first chlorine-containing by-product; d. contacting the first intermediate composition with a second fluorinating agent to produce a second intermediate composition including 2-chloro-1,1,1,2-tetrafluoropropane; and

and. dechlorhydrate at least a portion of the 2-chloro-1,1,1,2-tetrafluoropropane to produce a reaction product including 2,3,3,3-tetrafluoroprop-1-ene.

Additional embodiments and advantages of the present invention will be readily apparent to one skilled in the art, based on the disclosure provided herein.

Detailed description of the invention

In accordance with one embodiment, the present invention includes a manufacturing process for preparing 2,3,3,3-tetrafluoroprop-1-ene using a starting material according to any one or a combination of formulas I, II and / or III:

CX2 = CCl-CH2X (Formula I)

CXa-CCl = CH2 (Formula II)

CXa-CHCl-CH2X (Formula III)

wherein X is independently selected from F, Cl, Br, and I, provided that at least one X is not fluorine. In certain embodiments, the compound or compounds of Formula I, II and / or III contain at least one chlorine, most of the X as chlorine, or all X as chlorine. In certain embodiments, the compound or compounds of formula I include 1,1,2,3-tetrachloropropene (1230xa). In certain embodiments, the compound or compounds of formula II include 2,3,3,3-tetrachloropropene (1230xf). In further embodiments, the compound or compounds of formula III include 1,1,1,2,3-pentachloropropane (240db). The processes applicable to the present invention include, without limitation, integrated multistage processes as described in US Pat. No. 8,084,653 and US Published Patent Application 2009/0240090.

The method generally includes at least three reaction steps. In the first stage, a starting composition of Formulas I, II and / or III (such as 1,1,2,3-tetrachloropropene, 2,3,3,3-tetrachloropropene and / or 1,1,1,2 , 3-pentachloropropane) is reacted with anhydrous HF in a first vapor phase reactor (fluorination reactor) to produce a mixture of 2-chloro-3,3,3-trifluoropropene (1233xf) and HCl. In certain embodiments, the starting reagents are provided as a liquid phase and, prior to the reaction, are heated in a vaporizer to form a vapor phase. To this end, the conversion of the compounds of formulas I, II and / or III occurs in the vapor phase and in the presence of a vapor phase catalyst. A non-limiting catalyst can include, but is not limited to, a fluorinated chromium oxide. The catalyst may (or may not) have to be activated with anhydrous hydrogen fluoride HF (hydrogen fluoride gas) before use depending on the condition of the catalyst. In one embodiment, there is no oxygen-containing agent or gas supply, eg, air, pure oxygen, or dilute gaseous oxygen, such as an oxygen / inert gas (eg, nitrogen), to the first vapor phase reactor.

While fluorinated chromium oxides are described as the vapor phase catalyst, the present invention is not limited to this embodiment. Any fluorination catalyst known in the art can be used in this process. Some suitable catalysts include, but are not limited to chromium, aluminum, cobalt, manganese, nickel and iron oxides, hydroxides, halides, oxyhalides, inorganic salts thereof, and mixtures thereof, and any one of which may optionally be fluorinated. Suitable catalyst combinations for the present invention include not exclusively Cr2O3, FeCh / C, C ^ O3 / Al2O3, Cr2O3 / AlF3, Cr2O3 / carbon, COCh / Cr2O3 / AhO3, NiCl2 / Cr2O3 / Al2O3, CoCl2 / AlF3, NO2 / AF3 and mixtures thereof. Chromium oxide / aluminum oxide catalysts are described in US Pat. No. 5,155,082. Chromium (III) oxides such as crystalline chromium oxide or amorphous chromium oxide are preferred with amorphous chromium oxide being most preferred. Chromium oxide (Cr2O3) is a commercially available material that can be purchased in various particle sizes. Fluorination catalysts having a purity of at least 98% are preferred. The fluorination catalyst is present in an excess but in at least a sufficient amount to drive the reaction.

The compound of formulas I, II and / or III are also provided to the vaporizer with at least one supplemental organic compound and, optionally but preferably, hydrogen fluoride. The compound preferably, although not exclusively, has a boiling point that is lower than that of the compound of Formula I, II or III and should be chemically compatible with both the compound of these formulas and with hydrogen fluoride. Generally speaking, such compounds can include any halocarbon or haloolefin that exhibits the desired improvement in reaction and / or improvement in catalyst life. Some non-limiting examples of such halocarbons and haloolefins include one or any combination of trichlorofluoropropene (1231), 2,3-dichloro-3,3-difluoropropene (1232xf), 1,2-dichloro-3,3,3-trifluoropropene (1223xd ), 2-chloro-3,3,3-trifluoropropene (1233xf), 2-chloro-1,1,1,2tetrachloropropane (244bb), 1,1,1,2,2-pentafluoropropane (HFC-245cb), difluoromethane (HFC-32), pentafluoroethane (HFC-125), 1.1, 1,2-tetrafluoroethane (HFC-134a), trifluoroethane (HFC-143) (including all isomers thereof), 1,1,1,3,3-pentafluoropropane (HFC-245fa). In certain embodiments, the halocarbons and haloolefins include one or more organic compounds that are normally generated during the 1230xa fluorination reaction with h F, such as, but not limited to, 1231, 1232xf, 1223xd, 1233xf, 244bb, HFC- 245cb and combinations thereof.

The supplemental amount of compounds or an "effective amount", as used herein, refers to any supplemental amount provided to the vaporizer that can be used to enhance the conversion of a compound of formula I, II, and / or III (particularly 1230xa, 1230xf, and / or 240db) at 1233xf in the downstream reaction. In one aspect, the effective amount of supplemental organic compound can be any amount that measurably reduces the occurrence of oligomerization / polymerization of the compound of the above formulas during steam vaporization or during the fluorination reaction. Likewise, an effective amount can also, or independently, include any organic supplemental amount that results in a measurable reduction in catalyst deactivation, particularly deactivation caused by oligomerization / polymerization initiating reagent. In a non-limiting embodiment, the percentage of organic product or products co supplied in the total organic supply may vary from 0.1 to 99.9% by weight, from 1 to 50% by weight, from 3 to 30% by weight or 5 to 15% by weight, each based on the total weight of the organic reagents used. Although not wishing to be bound by theory, it is believed that supplementing at least one organic compound with a lower boiling point than the compound of formula I, II or III (particularly 1230xa, 1230xf or 240db) can facilitate vaporization of the starting compounds since the bubble point of the mixture is lower than that of the starting compounds and can help to avoid or at least reduce the formation of oligomers and / or polymers of starting reagents.

A vaporizer, as described herein, refers to a heat exchanger designed to convert a chemical compound from liquid to vapor form. Often the heating medium is steam, and therefore steam vaporizer is preferred. The vaporizer is preferably, but not exclusively, made of corrosion resistant materials. Non-limiting examples of corrosion resistant materials include Hastelloy, Nickel, Incoloy, Inconel, Monel, and fluoropolymer coatings.

In certain embodiments, liquid 1230xa, HF, and one or more of the supplements are continuously supplied to a steam vaporizer. Vapor pressure can vary over a wide range of 207-1724 kPa (30-250 psig), preferably 689-1379 kPa (100-200 psig), and even more preferably 965-1103 kPa (140-160 psig). The molar ratio of HF to HCO-1230xa is from 1: 1 to 50: 1 and preferably from about 10: 1 to about 20: 1. Depending on the pressure of the downstream reactor, the vaporizer can operate at a pressure of 1379 kPa (200 psig) or less, preferably 689 kPa (100 psig) or less, and even more preferably 483 kPa (70 psig) or less. The process temperature at the vaporizer outlet is inherently determined by its size and efficiency as well as by the steam and process conditions.

In additional embodiments, liquid 1230xf, HF, and one or more of the supplements are continuously supplied to a steam vaporizer. Vapor pressure can vary over a wide range of 207-1724 kPa (30-250 psig), preferably 689-1379 kPa (100-200 psig), and even more preferably 965-1103 kPa (140-160 psig). The molar ratio of HF to HCO-1230xf is from 1: 1 to 50: 1 and preferably from about 10: 1 to about 20: 1. Depending on the pressure of the downstream reactor, the vaporizer can operate at a pressure of 1379 kPa (200 psig) or less, preferably 689 kPa (100 psig) or less, and even more preferably 483 kPa (70 psig) or less. The process temperature at the vaporizer outlet is inherently determined by its size and efficiency as well as by the steam and process conditions.

In still further embodiments, 240db liquid, HF, and one or more of the supplements are continuously supplied to a steam vaporizer. Vapor pressure can vary over a wide range of 207-1724 kPa (30-250 psig), preferably 689-1379 kPa (100-200 psig), and even more preferably 965-1103 kPa (140-160 psig). The HF to 240db molar ratio is from 1: 1 to 50: 1 and preferably from about 10: 1 to about 20: 1. Depending on the pressure of the downstream reactor, the vaporizer can operate at a pressure of 1379 kPa (200 psig) or less, preferably 689 kPa (100 psig) or less, and even more preferably 483 kPa (70 psig) or less. The process temperature at the vaporizer outlet is inherently determined by its size and efficiency as well as by the steam and process conditions.

In either of the above embodiments, the vaporized mixture is then supplied to a fluorination reactor loaded with a fluorinated chromium catalyst to convert the mater or starting materials to 1233xf. The fluorination reaction can be carried out at a temperature of from about 150 ° C to about 400 ° C (preferably from about 180 ° C to about 300 ° C) and at a pressure of about 0 kPa (0 psig) to about 1379 kPa (200 psig), preferably from about 0 kPa (0 psig) to about 689 kPa (100 psig) and even more preferably from 0 kPa (0 psig) to 483 kPa (70 psig). The contact time of organic supplies with the catalyst can vary from about 1 second to about 60 seconds, however longer or shorter times can be used.

The fluorination reaction is preferably carried out to achieve a conversion of about 50 % or, preferably, about 90% or higher. The conversion is calculated by the number of moles of reagent consumed divided by the number of moles of reagent supplied to the reactor multiplied by 100. The selectivity for 1233xf achieved is preferably about 60% or more and more preferably about 80% or plus. The selectivity is calculated by the number of moles of product (1233xf) formed divided by the number of moles of reagent consumed.

This first stage of the reaction can be carried out in any reactor suitable for a vapor phase fluorination reaction. In certain embodiments, the reactor is constructed from materials that are resistant to the corrosive effects of hydrogen fluoride and the catalyst such as Hastalloy, Nickel, Incoloy, Inconel, Monel, and fluoropolymer coatings. The container is a fixed catalyst bed or fluidized bed. If desired, inert gases such as nitrogen or argon can be employed in the reactor during operation.

In general, the effluent from the fluorination reaction step, including any intermediate effluent that may be present in multiphase reactor arrangements, can be processed to achieve the desired degrees of separation and / or other processing. For example, in embodiments where the reactor effluent includes 1233xf, the effluent will generally also include HCl and one or more of HF, 2,3-dichloro-3,3-difluoropropene (1232xf), 1,2-dichloro-3, Unreacted 3,3-trifluoropropene (1223xd), trichlorofluoropropene (1231), 2-chloro-1,1,1,2-tetrachloropropane (244bb) and 1230xa, 1230xf and / or 240db isomers. Any portion or substantially all of these components of the reaction product can be recovered from the reaction mixture by any separation or purification method known in the art such as neutralization and distillation. Unreacted starting materials and HF are expected to be fully or partially recyclable to improve the overall yield of the desired 1233xf. 1232xf and any 1231 formed can also be recycled.

Optionally, the hydrogen chloride is recovered after the result of the fluorination reaction. The recovery of the hydrogen chloride is carried out by conventional distillation where it is removed from the distillate. Alternatively, HCl can be recovered or removed using water or caustic scrubbers. When a water extractor is used, the HCl is removed as an aqueous solution. When caustic scrubbers are used, e1HCl is removed from the system as a chloride salt in aqueous solution.

The second stage of the process to form 2,3,3,3-tetrafluoroprop-1-ene, 1233xf is converted to 2-chloro-1,1,1,2-tetrafluoropropane (244bb). In one embodiment, this step can be performed in the liquid phase in a liquid phase reactor, which can be coated with either TFE or PFA. Such a process can be performed over a temperature range of approximately 70-120 ° C and approximately 345-827 kPa (50-120 psig).

Any liquid phase fluorination catalyst can be used in the invention. A non-exhaustive list includes Lewis acids, transition metal halides, transition metal oxides, Group IVb metal halides, Group Vb metal halides, or combinations thereof. Some non-exclusive examples of liquid phase fluorination catalysts are an antimony halide, a tin halide, a tantalum halide, a titanium halide, a niobium halide and molybdenum halide, an iron halide, a chromium halide fluorinated, a fluorinated chromium oxide or combinations thereof. Specific non-exclusive examples of liquid phase fluorination catalysts are SbCl5, SbCl3, SbFs, SnCU, TaCU, TiCU, NbCU, MoCl6, FeCU, a fluorinated species of SbCl5, a fluorinated species of SbCl3, a fluorinated species of SnCU, a species fluorinated TaCU, a fluorinated species of TiCU, a fluorinated species of NbCU, a fluorinated species of MoCu, a fluorinated species of FeCU, or combinations thereof. Antimony pentachloride is the most preferred.

These catalysts can be easily regenerated by any means known in the art if they are deactivated. A suitable method of regenerating the catalyst involves flowing a stream of chlorine through the catalyst. For example, from about 0.9 to about 90 g per hour (0.002 to about 0.2 lb per hour) of chlorine can be added to the liquid phase reaction for every 454 g (1 pound) of liquid phase fluorination catalyst . This can be done, for example, for about 1 to about 2 hours or continuously at a temperature of about 65 ° C to about 100 ° C.

This second stage of the reaction is not necessarily limited to a liquid phase reaction and can also be performed using a vapor phase reaction or a combination of liquid and vapor phases, such as that disclosed in US Published Patent Application. USA No. 20070197842. To this end, the supply stream containing 1233xf is preheated to a temperature of about 50 ° C to about 400 ° C and is contacted with a catalyst and fluorinating agent. Catalysts can include conventional vapor phase agents used for such a reaction and fluorinating agents can include those generally known in the art, such as, but not limited to, hydrogen fluoride.

In the third stage of 1234yf production, the 244bb is supplied to a second vapor phase reactor (dehydrochlorination reactor) to dechlorhydrate to obtain the desired product 2,3,3,3-tetrafluoroprop-1-ene (1234yf) . This reactor contains a catalyst that can catalytically dehydrochloride HCFC-244bb to form HFO-1234yf.

Catalysts can be metal halides, halogenated metal oxides, neutral metal (or oxidation state) scratch) or metal alloy or activated carbon in bulk or supported form. Metal halide or metal oxide catalysts can include, but are not limited to, mono-, bi- and tri-valent metal halides, oxides and their mixtures / combinations and more preferably mono- and bivalent metal halides and their mixtures / combinations. Component metals include, but are not limited to, Cr3 +, Fe3 +, Mg2 +, Ca2 +, Ni2 +, Zn2 +, Pd2 +, Li +, Na +, K +, and Cs +. Component halogens include, but are not limited to, F-, Cl-, B reh. Examples of useful bi-valent monoo metal halides include, but are not limited to, LiF, NaF, KF, CsF, MgF2, CaF2, LiCl, NaCl, KCl and CsCl. Halogenation treatments can include any of those known in the prior art, particularly those that employ HF, F2, HCl, Cl2, HBr, Br2, HI and I2 as the halogenation source.

When metals, metal alloys and their neutral mixtures are used, that is, zero valent. Useful metals include, but are not limited to, Pd, Pt, Rh, Fe, Co, Ni, Cu, Mo, Cr, Mn, and combinations of the above as alloys or mixtures. The catalyst can be supported or unsupported. Useful examples of metal alloys include, but are not limited to, SS 316, Monel 400, Inconel 825, Inconel 600, and Inconel 625.

Preferred, but not limiting, catalysts include activated carbon, stainless steel (eg SS 316), nickel-based austenitic alloys (eg Inconel 625), nickel, 10% fluorinated CsCl / MgO and CsCl / MgF2 al 10%. The reaction temperature is preferably approximately 300-550 ° C and the reaction pressure can be between approximately 0-1034 kPa (0-150 psig). The reactor effluent can be fed to a caustic scrubber or a distillation column to remove the HCl by-product to produce an acid-free organic product that can optionally be subjected to further purification using one or any combination of purification techniques that are know in the art.

In one embodiment, the supplemental organic compounds are provided as fresh supplies in effective amounts, that is, they are not obtained from recycling streams derived from the multistage process.

In another embodiment, the supplemental organic compounds are present in one or more recycle streams derived from the multistage process as described in US Pat. No. 8,084,653 and US Published Patent Application 2009/0240090. In one practice of this embodiment, the invention is directed to a multistage process for preparing 2,3,3,3-tetrafluoropropene (1234yf) comprising a.) Providing, in a liquid phase, 1,1,2,3-tetrachloropropene (1230xa), a fluorinating agent and at least one supplemental organic compound, to a vaporizer; b.) vaporizing said 1,1,2,3-tetrachloropropene (1230xa), said fluorinating agent and said at least one supplement organic compound, to form a vaporized mixture; c.) contacting, in a first vapor phase reactor, said vaporized mixture with at least one compound of formula (I)

CX2 = CCl-CH2X (I)

wherein X is independently selected from F, Cl, Br and I, provided that at least one X is not fluorine, optionally in the presence of a vapor phase catalyst, to produce a first intermediate composition comprising 2-chlorine -3,3,3-trifluoropropene (1233xf) and HCl; b.) separating said HCl and said 2-chloro-3,3,3-trifluoropropene (1233xf) from said first intermediate composition;

c.) contacting, in a liquid phase reactor, said separated 2-chloro-3,3,3-trifluoropropene (1233xf) with a second fluorinating agent to produce a second intermediate composition comprising 2-chloro-1, 1,1,2-tetrafluoropropane (244bb); and e). dechlorhydrate, in a second vapor phase reactor, at least a portion of said 2-chloro-1,1,1,2-tetrafluoropropane (244bb) to produce a reaction product comprising 2,3,3,3-tetrafluoropropene . In another practice of this embodiment, said first intermediate composition further comprises at least one supplemental organic compound. In another practice, the process further comprised, in step b.), Separating said at least one supplemental organic compound from said first intermediate composition and recycling an effective amount of said at least one supplemental organic compound separated to said vaporizer in step a .). In one embodiment of this practice, said recycling is substantially free of 244bb and / or 245cb or contains these materials in amounts that are not effective amounts. In another practice, supplemental organic compounds are provided to the vaporizer as a combination of fresh and recycle supplies. In another practice, the process comprises, step a.), Said at least one organic supplement must be present in an effective amount and therefore reduce the formation of oligomers and / or polymers in said vaporizer. In another practice, said fluorinating agent is HF and said optional vapor phase catalyst is a chromium oxide, a chromium hydroxide, a chromium halide, a chromium oxyhalide, an aluminum oxide, an aluminum hydroxide, a aluminum halide, an aluminum oxyhalide, a cobalt oxide, a cobalt hydroxide, a cobalt halide, a cobalt oxyhalide, a manganese oxide, a manganese hydroxide, a manganese halide, a manganese oxyhalide, a nickel oxide, nickel hydroxide, nickel halide, nickel oxyhalide, iron oxide, iron hydroxide, iron halide, iron oxyhalide, inorganic salts thereof, fluorinated derivatives thereof and combinations thereof.

Examples

Example 1

This example illustrates the effect of supplementing 1232xf or 1233xf along with 1230xa and HF on vaporization of 1230xa and the formation of non-volatile residues.

A system consisting of N2, HF and organic supply systems, steam vaporizer, 2 cm (% ") external diameter U-shaped superheater (immersed in a sand bath), and an acidic scrubber was used for the vaporization study.High pressure (1034 kPa (150 psig)) steam was used at full speed to heat the vaporizer.The process pressure was controlled by controlling the pressure in a U-shaped superheater, which was maintained at 180 ° C HF and organic products (1230xa, 10% 1232xf / 90% 1230xa, or 10% 1233xf / 90% 1230xa) were introduced into the steam vaporizer and then into the U-shaped superheater at supply rates of 0, 91 kg / h and 0.45 kg / h (2.0 lb / h and 1.0 lb / h), respectively After eight hours, the mixed supply and steam were stopped and the vaporizer was cooled under nitrogen flow. At room temperature, the contents accumulated in the steam vaporizer were drained and weighed, after which ag was added. ua and methylene chloride to the drained sample and phase separation was performed. A fraction of the separated organic phase was subjected to residual non-volatile determination (NVR). As shown in Table 1, supplementing 1232xf or 1233xf significantly reduced build-up in the steam vaporizer except for the 20 psig (138 kPa) pressure point and the total amount of NVR at all pressures.

Table 1

Example 2

The 1230xa used in this example contained 5 ppm of diisopropylamine. A 10 wt% blend of 1233xf-90 wt% 1230xa was prepared as raw material. 6.5 L of pre-fluorinated chromium oxide catalyst was loaded into a 10 cm (4 inch) Monel 400 reactor. The reactor was heated to approximately 180 ° C under nitrogen flow. The anhydrous HF feed was then started at a flow rate of 0.86 kg / h (1.9 lb / h). After passing through a Mol Sieve 3A column at a flow rate of 0.50 kg / h (1.1 lb / h), the organic supply was combined with the HF supply. The mixed supply of HF and organic was introduced into a vaporizer for vaporization and then into the reactor for reaction. The reaction temperature (hot spot temperature) was increased to approximately 200 ° C once the reaction started. The reactor pressure was adjusted to 483 kPa (70 psig). Samples were taken periodically from the product stream and analyzed by GC and GC-MS during the reaction. The results showed that the conversion of 1230xa was almost 100% and the average selectivities of 1233xf, 1232xf, 244bb were approximately 97.9%, 0.3% and 1.5%, respectively, during the time period of the study of reaction that lasted approximately 300 hours.

Claims (12)

1. A process to reduce the polymerization of a starting reagent comprising: providing a liquid phase composition comprising a compound of formulas I, II and / or III CX2 = CCl-CH2X (Formula I) CXa-CCl = CH2 (Formula II) CXa-CHCl-CH2X (Formula III) and one or more supplemental organic compounds other than the compound of formulas I, II and / or III, wherein X is independently selected from F, Cl, Br and I, provided that at least one X is not fluorine; and heating said starting composition to form a vapor phase composition, said supplemental organic compound being present in an amount ranging from 1 to 50% by weight, preferably from 3 to 30% by weight and more preferably from 5 to 15% by weight and wherein said organic supplement is a halocarbon or haloolefin and has a boiling point that is lower than the boiling point for the compound of Formulas I, II 0 III and where the organic supplement is chemically compatible with the compound of Formulas I, II or III and with hydrogen fluoride. 2. A process for preparing 2-chloro-3,3,3-trifluoropropene, comprising: providing in a liquid phase a starting composition comprising at least one compound of formulas I, II and / or III: CX2 = CCl-CH2X (Formula I) CX3-CCl = CH2 (Formula II) CX3-CHCl-CH2X (Formula III) wherein X is independently selected from F, Cl, Br and I, provided that at least one X is not fluorine; and vaporizing said starting composition with one or more supplemental organic compounds, other than the compound of formulas I, II and / or III, to form a vapor phase composition according to claim 1 in the presence of a fluorinating agent, preferably hydrogen fluoride, said one or more supplemental organic compounds being present in an amount ranging from 1 to 50% by weight, preferably from 3 to 30% by weight and more preferably from 5 to 15% by weight and wherein said organic supplement it is a halocarbon or haloolefin and has a boiling point that is lower than the boiling point for the compound of Formulas I, II or III and where the organic supplement is chemically compatible with the compound of Formulas I, II or III and with hydrogen fluoride; and contacting said vaporized starting composition and an effective amount of said vaporized fluorination agent in the presence of a fluorination catalyst to produce a final composition comprising 2-chloro-3,3,3-trifluoropropene. 3. The process of claim 1, wherein in the liquid phase the composition further comprises hydrogen fluoride. 4. The process of any one of claims 1-3, wherein the supplemental organic compound is selected from the group consisting of trichlorofluoropropene (1231), 2,3-dichloro-3,3-difluoropropene (1232xf), 1,2 -dichloro-3,3,3-trifluoropropene (1223xd), 2-chloro-3,3,3-trifluoropropene (1233xf), 2-chloro-1,1,1,2-tetrachloropropane (244bb), 1,1, 1,2,2-pentafluoropropane (HFC-245cb), difluoromethane (HFC-32), pentafluoroethane (HFC-125), 1,1,1,2-tetrafluoroethane (HFC-134a), trifluoroethane (HFC-143), 1 , 1,1,3,3-pentafluoropropane (HFC-245fa) and combinations thereof. 5. The process of any one of claims 1-4, wherein at least one compound of formulas I, II or III is a compound comprising at least one X which is chlorine, preferably wherein at least one compound of formulas I, II or III is a compound where all X are chlorine. 6. The process of any one of claims 1-5, wherein the at least one compound of formula I comprises 1,1,2,3-tetrachloropropene or wherein the at least one compound of formula II comprises 2,3, 3,3-tetrachloropropene or wherein the at least one compound of formula III comprises 1,1,1,2,3-pentachloropropane. 7. The process of any one of claims 1-6, wherein contact of said starting composition with a fluorinating agent occurs in a vapor phase. 8. The process of any one of claims 1-7, wherein the fluorination catalyst is a catalyst in vapor phase, preferably wherein the vapor phase catalyst is selected from the group consisting of a chromium oxide, a chromium hydroxide, a chromium halide, a chromium oxyhalide, an aluminum oxide, an aluminum hydroxide, an aluminum halide, an aluminum oxyhalide, a cobalt oxide, a cobalt hydroxide, a cobalt halide, a cobalt oxyhalide, a manganese oxide, a manganese hydroxide, a manganese halide, a manganese oxyhalide, a nickel oxide, a nickel hydroxide, a nickel halide, a nickel oxyhalide, an iron oxide, an iron hydroxide, an iron halide, an iron oxyhalide, inorganic salts thereof, fluorinated derivatives of themselves and combinations thereof, more preferably where the catalyst comprises a chromium oxide and even more preferably where the catalyst comprises Cr2O3. 9. A process for preparing 2,3,3,3-tetrafluoroprop-1-ene (1234yf) comprising: contacting a first intermediate composition comprising 2-chloro-3,3,3-trifluoropropene manufactured according to claim 2 with a second fluorinating agent to produce a second intermediate composition comprising 2-chloro-1,1,1 , 2-tetrafluoropropane; and dechlorhydrate at least a portion of said 2-chloro-1,1,1,2-tetrafluoropropane to produce a reaction product comprising 2,3,3,3-tetrafluoroprop-1-ene. 10. A multistage process to prepare 2,3,3,3-tetrafluoropropene (1234yf), comprising: a.) providing, in a liquid phase, 1,1,2,3-tetrachloropropene (1230xa), a first fluorinating agent and at least one supplemental organic compound, to a vaporizer; said supplemental organic compound being present in an amount ranging from 1% by weight to 50% by weight, preferably from 3% by weight to 30% by weight and more preferably from 5% by weight to 15% by weight and other than a compound of formulas I, II or III CX = CCl-CH2 X Formula I CX3 - CCl = CH2 (Formula II) CX3-CHCl-CH2X (Formula III) wherein X is independently selected from F, Cl, Br and I, provided that at least one X is not fluorine b. ) vaporizing said 1,1,2,3-tetrachloropropene (1230xa), said first fluorinating agent and said at least one supplemental organic compound, to form a vaporized mixture; c. ) contacting, in a first vapor phase reactor, said vaporized mixture with at least one compound of formula I CX2 = CCl-CH2X (I) wherein X is independently selected from F, Cl, Br and I, provided that at least one X is not fluorine, optionally in the presence of a vapor phase catalyst, to produce a first intermediate composition comprising 2-chlorine -3,3,3-trifluoropropene (1233xf) and Hcl; d. ) separating said HCl, and at least a portion of said 2-chloro-3,3,3-trifluoropropene (1233xf), from said first intermediate composition; and. ) contacting, in a liquid phase reactor, said separated 2-chloro-3,3,3-trifluoropropene (1233xf) with a second fluorinating agent to produce a second intermediate composition comprising 2-chloro-1,1, 1,2-tetrafluoropropane (244bb); and F. ) dechlorohydrate, in a second vapor phase reactor, at least a portion of said 2-chloro-1,1,1,2-tetrafluoropropane (244bb) to produce a reaction product comprising 2,3,3,3- tetrafluoropropene, wherein said organic co-feed is a halocarbon or haloolefin and has a boiling point that is below the boiling point for the compound of Formulas I, II or III and where the organic supplement is chemically compatible with the compound of Formulas I, II or III and with the first fluorinating agent. The process of claim 10, wherein said first intermediate composition further comprises at least one supplemental organic compound, optionally further comprising in step b.) Separating said at least one supplemental organic compound from said first intermediate composition and recycling a effective amount of said at least one supplemental organic compound separated to said vaporizer in step a.). 12. The process of any one of claims 10-11 wherein said fluorinating agent is HF and said optional vapor phase catalyst is a chromium oxide, a chromium hydroxide, a chromium halide, a chromium oxyhalide, an aluminum oxide, an aluminum hydroxide, an aluminum halide, an aluminum oxyhalide, a cobalt oxide, a cobalt hydroxide, a cobalt halide, a cobalt oxyhalide, a manganese oxide, a manganese hydroxide, a manganese halide, a manganese oxyhalide, a nickel oxide, a nickel hydroxide, a nickel halide, a nickel oxyhalide, an iron oxide, an iron hydroxide, an iron halide, an iron oxyhalide, inorganic salts thereof, fluorinated derivatives thereof and combinations thereof.